Generally, a compressor using a vane divides an inner space of a cylinder into a suction area and a compression area by installing the vane to be contacted to a rotator body, changes the suction area and the compression area with each other successively according to phases of the rotating body when the rotating body is operated to suck, to compress, and to discharge fluid.
FIG. 1 is a longitudinal cross-sectional view showing an example of a conventional hermetic compressor.
As shown therein, the conventional hermetic compressor comprises: a motor device unit consisting of a stator (Ms) and a rotor (Mr) for generating driving power on an inner upper portion of a casing 1, and a compression device unit connected to the rotor (Mr) for sucking, compressing and discharging the fluid.
The compression device unit comprises: a cylinder 2 fixed on a lower part of the casing 1; a first bearing plate 3A and a second bearing plate 3B fixed on an upper surface and on a lower surface of the cylinder 2 to form an inner space of the cylinder 2; a rotating shaft 4 coupled to the rotor (Mr) of the motor device unit and penetratingly coupled to the respective bearing plates 3A and 3B for transmitting the driving power of the motor device unit to the compression device unit; a dividing plate 5 coupled to the rotating shaft 4 or molded integrally with the rotating shaft 4 for dividing the inner space of the cylinder 2 into a first space (S1) and a second space (S2); a first vane 6A and a second vane 6B having lower ends and upper ends contacted to both surfaces of the dividing plate 5 respectively for dividing the respective spaces S1 and S2 into the suction area and the compression area when the rotating shaft 4 is rotated; and a first spring assembly 8A and a second spring assembly 8B for elastically supporting the respective vanes 6A and 6B.
The dividing plate 5 is formed as a disc when it is projected on a plane so that an outer circumferential surface thereof can be slidingly contacted to an inner circumferential surface of the cylinder 2, and both side surfaces of the dividing plate 5 are formed as cam faces of sine wave shape having same thickness from the inner circumferential surface to the outer circumferential surface when these are spread.
In addition, the first and second vanes 6A and 6B are formed as cuboids, penetrate the respective bearing plates 3A and 3B to be contacted to the lower and upper cam faces of the dividing plate 5 as described above, and reciprocate toward the shaft direction when the rotating shaft 4 is rotated. Outer side surfaces of the respective vanes 6A and 6B are contacted or inserted in the inner circumferential surface of the cylinder 2, however, inner side surfaces of the respective vanes 6A and 6B are coupled to be contacted to the outer circumferential surface of the rotating shaft 4 as slid.
Also, the first spring assembly 8A and the second spring assembly 8B comprise a first and a second supporting springs 8a and 8c made of coil compressive spring for supporting rear surfaces of the respective vanes 6A and 6B, and a first spring holder 8b and a second spring holder 8d for receiving the respective supporting springs 8a and 8c and mounted on the first bearing plate 3A and on the second bearing plate 3B.
In Figures, unexplained reference numerals 2a and 2b represent suction openings of the respective spaces S1 and S2, 3a and 3b represent discharge openings, 7A and 7B represent discharge mufflers, 7a and 7b are discharge holes, DP is a discharge pipe, and SP represents a suction pipe.
Hereinafter, operations of the conventional hermetic compressor as above will be described.
When electric power is applied to the motor device unit to rotate the rotor (Mr), the rotating shaft 4 coupled to the rotor (Mr) is rotated to one direction with the dividing plate 5, and the vanes 6A and 6B contacted to upper and lower side surfaces of the dividing plate 5 reciprocate to opposite directions of each other according to the height (phase) of the dividing plate 5 to vary volumes of the first and second spaces S1 and S2. And new fluid is sucked simultaneously through the suction openings 2a and 2b of the first and second spaces S1 and S2, then compressed, and after that, the compressed fluid is discharged through the discharge openings 3a and 3b of the respective spaces S1 and S2 as soon as a top dead center or a bottom dead center of the dividing plate 5 reaches to a discharge starting point.
However, in the conventional compressor as above, the first and second supporting springs 8a and 8c supporting the respective vanes 6A and 6B are made of coil compressive springs having predetermined lengths in shaft direction, and therefore, a predetermined distance (L1) should be maintained between the first supporting spring 8a and the coil of the stator (Ms) as shown in FIG. 2. Therefore, the length of the compressor in shaft direction is increased.